Electron micrographs of exosomes derived from primary microglia treated with Wnt3a. Microglia (2500000 cells) were treated with Wnt3a (10 nM) for 8 hours in SFM. Cell culture medium was collected, centrifuged at 10000xg for 10 minutes, concentrated using 3kDa centrifugal devices and exosomes were isolated at 100000xg. Exosomes were fixed then either negatively stained with uranyl acetate (0.3%) in methyl cellulose (2%) following immuno-gold staining with anti-β actin (A) or anti-Wnt3a (B) or positively stained using 1% osmium tetraoxide (C). Exosomes were visualised using a FEI Tecnai T12 BioTWIN transmission electron microscope. A and B: colloidal gold represents 10 nm. C: scale bar represents 100 nm.